Kane played the whole World Cup season in England, as well as 90 minutes in the 1: 2 defeat to Spain and half an hour against Switzerland.
Danny Murphy and Craig Bellamy agreed with the debate that Kane is not nearly his best at the moment.
The England international scored twice as the Reds suffered a 4-1 defeat at Tottenham in October at Wembley.
Kane was at the head of his game as Spurs marched on and used the naive Liverpool defense.
But the game came before Jurgen Klopp spent 75 million pounds on Dutch defender Virgil van Dijk in the January transfer window.
And the two ex-Reds believe that a lack of calm will hamper Keyn and increase Liverpool's chances when the teams meet on Saturday (12:30).
"He's a striker who gives everything and not all strikers," Murphy said of the 25-year-old striker.
"Sometimes superstars and matchwinners protect themselves better than him.
"He always plays 90 minutes"
"He does not do that, he stands out there, unlike Sergio Aguero or Romelu Lukaku, he always plays 90 minutes."
"With 75 percent, even Kane could win the game on Saturday.
"He has done an incredible job last season.
"I would be surprised if he produces that again, but that does not mean it can not happen.
When asked if he had any indication that Kane was adjusting to his fatigue, Bellamy said he did.
"He is coming much deeper now," added the former striker. "If you do not want to run after you, you come deep into the ball.
"If I was not in the position I needed to be, I would fall low and make the game easier for me.
"I did not want to go and sprint because it took too much energy from me."